Acid-Base Worksheet #7
Polyatomic Acids & Bases
1. Phosphorus acid, H3PO4, is actually a diprotic acid; Ka1 = 1.0 X 10-2 and  Ka2 = 2.6 X 10-7. What are the values of [H+], pH and HPO32- in a 1.0 M solution?
 
2. Tellurium, in the same family as sulphur, forms an acid analogous to sulphuric acid and called telluric acid. It exists, however, as H6TeO6 (which looks like H2TeO4 + 2 H2O). It is a diprotic acid. Ka1 = 2.1 X 10-8 and Ka2 = 6.5 X 10-12. Calculate [H+], pH, and [H4TeO62-] in a 0.25 M solution of H6TeO6
 
3. How many millilitres of 0.05 M phosphoric acid will be required for reaction with 50 mL of 0.50 M KOH to yield a) KH2PO4, b) K2HPO4, c) K3PO4
 
4.  Write formulas for the primary, secondary, and tertiary lithium salts of H3PO4. Write equations for the equilibria present in an aqueous solution of a) H2SO4, b) H3PO4.